1. Field of the Invention
Methods and apparatuses consistent with the present invention relate to improving picture quality in a composite video burst signal, and removing artifacts in a composite video burst signal.
2. Description of the Related Art
In a process of encoding video information in a National Television System Committee (NTSC) system, a signal is encoded such that a luminance signal is modulated onto the low frequency part of the signal, and a chrominance signal is modulated onto the high frequency part of the signal. This signal is called a composite video burst signal (CVBS), and through a transmission and reception process, white Gaussian noise (WGN) is added to this signal. When the noise is thus added to the composite video burst signal, both the luminance and chrominance signals are affected. Accordingly, noise having a variety of colors as well as noise having black and white colors appears, and the picture quality deteriorates. In order to reduce degradation of the picture quality, much research has been carried out.
FIG. 1 is a block diagram illustrating a related art apparatus for improving picture quality.
Referring to FIG. 1, in the related art apparatus for improving picture quality, if a composite video burst signal XCVBS is input to a decoder 102, the decoder 102 separates the composite video burst signal XCVBS into a luminance signal and a chrominance signal. The decoder 102 extends the one-dimensional (1D) signal to a two-dimensional (2D) or three-dimensional (3D) signal by applying a line delay and a frame delay, and filters the signal through a filter included in the decoder 102. An artifact detection and removal unit 104 performs filtering of the signal XRGB decoded by the decoder 102, and outputs an artifact-free signal X′RGB.
In the related art apparatus for improving picture quality described above, it is assumed that the noise in the video signal XRGB after the decoding is white Gaussian noise. Furthermore, it is assumed that the noise is in a luminance signal, which has the most information in the video signal, and thus removal of noise is performed in relation to only the luminance signal. However, in the case of actual noise occurring in the process of transmitting and receiving a television signal, noise is added in the process of transforming signals into a composite video burst signal, and thus, noise having a color component is generated in addition to the luminance signal noise.
Accordingly, after a composite video burst signal including noise is decoded, if noise in a video signal XRGB is analyzed, it can be seen that the noise is composed of dots having black-and-white components and a variety of colors. Also, it can be seen that the pattern of the noise in the composite video burst signal is different from that of 2D white Gaussian noise, which is used in the related art apparatus. The characteristic of the white Gaussian noise changes according to a decoder used in the process of decoding, and thus, the noise becomes a color noise form on a video plane.
The related art apparatus for improving picture quality cannot apply an appropriate algorithm to this noise, and thus, the improvement of picture quality by the related art apparatus is not effective.